1. Field of the Invention
This invention relates to an electric mirror angle adjusting device for a mirror mounted on a door, a fender or the like, of a motor vehicle. Particularly, the invention relates to an electric mirror angle adjusting device adapted to adjust the angle of reflection of the mirror by means of two actuators, characterized by having means for properly controlling the direction of inclination, horizontal or vertical, of the mirror so as to prevent the mirror from being obliquely displaced during the operation of the motor vehicle. Also, the invention facilitates the assembly of a rear-view mirror having three pivots.
2. Description of the Prior Art
Devices adapted to remotely control the angle of reflection of a rear-view mirror by means of two actuators are disclosed, for instance, in U.S. Pat. Nos. 3,609,014 and 3,972,597. Each of these devices comprises a supporting pivot for the mirror disposed in the center of an actuator unit housing, and two movable pivots therefor disposed away from said supporting pivot respectively on a horizontal axis and a vertical axis, meeting at right angles with each other, said movable pivots being movable back and forth by their actuators so as to adjust the horizontal angle and vertical angle of the mirror. Although the center of a spherical bearing for each of said movable pivots actually moves along a circular arc with its center at the supporting pivot, each of said movable pivots is adapted to move along a straight line because it is fixed to the output shaft of its actuator or to an externally threaded rod engaging with the central hole of a worm wheel of the actuator. Therefore, the movable pivots do not follow the movements of their spherical bearings, and smooth operation is not obtained. Furthermore, at the time of assembly, the pivots may not be accurately fitted in their proper positions.
Thus, the inventor has provided, in U.S. patent application Ser. No. 077,390, now U.S. Pat. No. 4,324,454, an electric mirror angle adjusting device comprising a pair of pivot screws each being pivotally attached within the central hole of a worm wheel of an actuator, an adjusting nut with a plurality of catches engaging with each pivot screw, and a movable pivot being provided at one end of each adjusting nut, so that each movable pivot not only moves back and forth but also swings conically on the root of its pivot screw as its spherical bearing moves along a circular arc. Therefore, in this device the angular adjustment of the mirror can be made smoothly, and assembly work is facilitated.
Since each movable pivot is adapted to swing conically on the root of its pivot screw as mentioned above, this device has, at the same time, the disadvantage that the mirror is not held firmly at its adjusted angle and therefore it may be obliquely displaced, that is, from its intended viewing position, by the vibration of the motor vehicle.